This invention relates to topical ophthalmic compositions comprising certain 4-(3-substituted amino-2-hydroxypropoxy)-1,2,5-thiadiazoles. These compounds are .beta.-blockers which are effective at relatively low doses. Ophthalmic compositions comprising these compounds are useful in the treatment of glaucoma and ocular hypertension.
This class of compounds was originally disclosed in German Patent No. 1,925,956 (issued in 1969 to B. K. Wasson), which is equivalent to U.S. No. 3,655,663 (issued in 1972) and U.S. No. 3,729,469 (issued in 1973). It was later found that topical application of timolol, one of the most effective thiadiazoles disclosed and claimed in U.S. No. 3,655,663 (the '663 patent), was also useful to treat ocular hypertension. See, for example, Heel, et al., Drugs, 17:38-55 (1979). Although effective in decreasing intraocular pressure, there are often rather severe systemic side effects associated with the use of topical ophthalmic compositions of timolol. Because timolol was the most potent of the compounds tested, other compounds of the class disclosed in the '663 patent were thought to be unsuitable for the treatment of ocular hypertension, as the larger doses which would be needed would be intolerable due to the corresponding increase in systemic and ocular side effects.